Breast cancer risk increased by diagnostic radiation

Breast cancer is a concern when considering exposure to the ionizing radiation used in x-rays, CT scans and mammography. Research just published in the British Journal of Medicine brings to light evidence that breast cancer risk is significantly increased with exposure to diagnostic radiation among carriers of the BRCA1/2 gene mutation. The authors of this large study set out to...

"...estimate the risk of breast cancer associated with diagnostic radiation in carriers of BRCA1/2 mutations.

They examined data for 1993 women in France, United Kingdom and the Netherlands who carried the BRCA1/2 mutations, correlating the cumulative breast dose of radiation from diagnostic procedures with the incidence of breast cancer. The data strongly suggest that diagnostic radiation should be minimized by BRCA1/2 carriers:

"In carriers of BRCA1/2 mutations any exposure to diagnostic radiation before the age of 30 was associated with an increased risk of breast cancer, with a dose-response pattern...Analyses on the different types of diagnostic procedures showed a pattern of increasing risk with increasing number of radiographs before age 20 and before age 30 compared with no exposure. A history of mammography before age 30 was also associated with an increased risk of breast cancer (hazard ratio 1.43, 0.85 to 2.40). Sensitivity analysis showed that this finding was not caused by confounding by indication of family history."

These findings are specific for carriers of the BRCA1/2 gene, but would not prudence dictate a careful and judicious use of diagnostic radiation for everyone? There are alternatives as the authors note in their conclusion:

"In this large European study among carriers of BRCA1/2 mutations, exposure to diagnostic radiation before age 30 was associated with an increased risk of breast cancer at dose levels considerably lower than those at which increases have been found in other cohorts exposed to radiation. The results of this study support the use of non-ionising radiation imaging techniques (such as magnetic resonance imaging) as the main tool for surveillance in young women with BRCA1/2 mutations."